1 | // |
2 | // buffer_registration.hpp |
3 | // ~~~~~~~~~~~~~~~~~~~~~~~ |
4 | // |
5 | // Copyright (c) 2003-2024 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
6 | // |
7 | // Distributed under the Boost Software License, Version 1.0. (See accompanying |
8 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
9 | // |
10 | |
11 | #ifndef BOOST_ASIO_BUFFER_REGISTRATION_HPP |
12 | #define BOOST_ASIO_BUFFER_REGISTRATION_HPP |
13 | |
14 | #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
15 | # pragma once |
16 | #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
17 | |
18 | #include <boost/asio/detail/config.hpp> |
19 | #include <iterator> |
20 | #include <utility> |
21 | #include <vector> |
22 | #include <boost/asio/detail/memory.hpp> |
23 | #include <boost/asio/execution/context.hpp> |
24 | #include <boost/asio/execution/executor.hpp> |
25 | #include <boost/asio/execution_context.hpp> |
26 | #include <boost/asio/is_executor.hpp> |
27 | #include <boost/asio/query.hpp> |
28 | #include <boost/asio/registered_buffer.hpp> |
29 | |
30 | #if defined(BOOST_ASIO_HAS_IO_URING) |
31 | # include <boost/asio/detail/scheduler.hpp> |
32 | # include <boost/asio/detail/io_uring_service.hpp> |
33 | #endif // defined(BOOST_ASIO_HAS_IO_URING) |
34 | |
35 | #include <boost/asio/detail/push_options.hpp> |
36 | |
37 | namespace boost { |
38 | namespace asio { |
39 | namespace detail { |
40 | |
41 | class buffer_registration_base |
42 | { |
43 | protected: |
44 | static mutable_registered_buffer make_buffer(const mutable_buffer& b, |
45 | const void* scope, int index) noexcept |
46 | { |
47 | return mutable_registered_buffer(b, registered_buffer_id(scope, index)); |
48 | } |
49 | }; |
50 | |
51 | } // namespace detail |
52 | |
53 | /// Automatically registers and unregistered buffers with an execution context. |
54 | /** |
55 | * For portability, applications should assume that only one registration is |
56 | * permitted per execution context. |
57 | */ |
58 | template <typename MutableBufferSequence, |
59 | typename Allocator = std::allocator<void>> |
60 | class buffer_registration |
61 | : detail::buffer_registration_base |
62 | { |
63 | public: |
64 | /// The allocator type used for allocating storage for the buffers container. |
65 | typedef Allocator allocator_type; |
66 | |
67 | #if defined(GENERATING_DOCUMENTATION) |
68 | /// The type of an iterator over the registered buffers. |
69 | typedef unspecified iterator; |
70 | |
71 | /// The type of a const iterator over the registered buffers. |
72 | typedef unspecified const_iterator; |
73 | #else // defined(GENERATING_DOCUMENTATION) |
74 | typedef std::vector<mutable_registered_buffer>::const_iterator iterator; |
75 | typedef std::vector<mutable_registered_buffer>::const_iterator const_iterator; |
76 | #endif // defined(GENERATING_DOCUMENTATION) |
77 | |
78 | /// Register buffers with an executor's execution context. |
79 | template <typename Executor> |
80 | buffer_registration(const Executor& ex, |
81 | const MutableBufferSequence& buffer_sequence, |
82 | const allocator_type& alloc = allocator_type(), |
83 | constraint_t< |
84 | is_executor<Executor>::value || execution::is_executor<Executor>::value |
85 | > = 0) |
86 | : buffer_sequence_(buffer_sequence), |
87 | buffers_( |
88 | BOOST_ASIO_REBIND_ALLOC(allocator_type, |
89 | mutable_registered_buffer)(alloc)) |
90 | { |
91 | init_buffers(buffer_registration::get_context(ex), |
92 | boost::asio::buffer_sequence_begin(buffer_sequence_), |
93 | boost::asio::buffer_sequence_end(buffer_sequence_)); |
94 | } |
95 | |
96 | /// Register buffers with an execution context. |
97 | template <typename ExecutionContext> |
98 | buffer_registration(ExecutionContext& ctx, |
99 | const MutableBufferSequence& buffer_sequence, |
100 | const allocator_type& alloc = allocator_type(), |
101 | constraint_t< |
102 | is_convertible<ExecutionContext&, execution_context&>::value |
103 | > = 0) |
104 | : buffer_sequence_(buffer_sequence), |
105 | buffers_( |
106 | BOOST_ASIO_REBIND_ALLOC(allocator_type, |
107 | mutable_registered_buffer)(alloc)) |
108 | { |
109 | init_buffers(ctx, |
110 | boost::asio::buffer_sequence_begin(buffer_sequence_), |
111 | boost::asio::buffer_sequence_end(buffer_sequence_)); |
112 | } |
113 | |
114 | /// Move constructor. |
115 | buffer_registration(buffer_registration&& other) noexcept |
116 | : buffer_sequence_(std::move(other.buffer_sequence_)), |
117 | buffers_(std::move(other.buffers_)) |
118 | { |
119 | #if defined(BOOST_ASIO_HAS_IO_URING) |
120 | service_ = other.service_; |
121 | other.service_ = 0; |
122 | #endif // defined(BOOST_ASIO_HAS_IO_URING) |
123 | } |
124 | |
125 | /// Unregisters the buffers. |
126 | ~buffer_registration() |
127 | { |
128 | #if defined(BOOST_ASIO_HAS_IO_URING) |
129 | if (service_) |
130 | service_->unregister_buffers(); |
131 | #endif // defined(BOOST_ASIO_HAS_IO_URING) |
132 | } |
133 | |
134 | /// Move assignment. |
135 | buffer_registration& operator=(buffer_registration&& other) noexcept |
136 | { |
137 | if (this != &other) |
138 | { |
139 | buffer_sequence_ = std::move(other.buffer_sequence_); |
140 | buffers_ = std::move(other.buffers_); |
141 | #if defined(BOOST_ASIO_HAS_IO_URING) |
142 | if (service_) |
143 | service_->unregister_buffers(); |
144 | service_ = other.service_; |
145 | other.service_ = 0; |
146 | #endif // defined(BOOST_ASIO_HAS_IO_URING) |
147 | } |
148 | return *this; |
149 | } |
150 | |
151 | /// Get the number of registered buffers. |
152 | std::size_t size() const noexcept |
153 | { |
154 | return buffers_.size(); |
155 | } |
156 | |
157 | /// Get the begin iterator for the sequence of registered buffers. |
158 | const_iterator begin() const noexcept |
159 | { |
160 | return buffers_.begin(); |
161 | } |
162 | |
163 | /// Get the begin iterator for the sequence of registered buffers. |
164 | const_iterator cbegin() const noexcept |
165 | { |
166 | return buffers_.cbegin(); |
167 | } |
168 | |
169 | /// Get the end iterator for the sequence of registered buffers. |
170 | const_iterator end() const noexcept |
171 | { |
172 | return buffers_.end(); |
173 | } |
174 | |
175 | /// Get the end iterator for the sequence of registered buffers. |
176 | const_iterator cend() const noexcept |
177 | { |
178 | return buffers_.cend(); |
179 | } |
180 | |
181 | /// Get the buffer at the specified index. |
182 | const mutable_registered_buffer& operator[](std::size_t i) noexcept |
183 | { |
184 | return buffers_[i]; |
185 | } |
186 | |
187 | /// Get the buffer at the specified index. |
188 | const mutable_registered_buffer& at(std::size_t i) noexcept |
189 | { |
190 | return buffers_.at(i); |
191 | } |
192 | |
193 | private: |
194 | // Disallow copying and assignment. |
195 | buffer_registration(const buffer_registration&) = delete; |
196 | buffer_registration& operator=(const buffer_registration&) = delete; |
197 | |
198 | // Helper function to get an executor's context. |
199 | template <typename T> |
200 | static execution_context& get_context(const T& t, |
201 | enable_if_t<execution::is_executor<T>::value>* = 0) |
202 | { |
203 | return boost::asio::query(t, execution::context); |
204 | } |
205 | |
206 | // Helper function to get an executor's context. |
207 | template <typename T> |
208 | static execution_context& get_context(const T& t, |
209 | enable_if_t<!execution::is_executor<T>::value>* = 0) |
210 | { |
211 | return t.context(); |
212 | } |
213 | |
214 | // Helper function to initialise the container of buffers. |
215 | template <typename Iterator> |
216 | void init_buffers(execution_context& ctx, Iterator begin, Iterator end) |
217 | { |
218 | std::size_t n = std::distance(begin, end); |
219 | buffers_.resize(n); |
220 | |
221 | #if defined(BOOST_ASIO_HAS_IO_URING) |
222 | service_ = &use_service<detail::io_uring_service>(ctx); |
223 | std::vector<iovec, |
224 | BOOST_ASIO_REBIND_ALLOC(allocator_type, iovec)> iovecs(n, |
225 | BOOST_ASIO_REBIND_ALLOC(allocator_type, iovec)( |
226 | buffers_.get_allocator())); |
227 | #endif // defined(BOOST_ASIO_HAS_IO_URING) |
228 | |
229 | Iterator iter = begin; |
230 | for (int index = 0; iter != end; ++index, ++iter) |
231 | { |
232 | mutable_buffer b(*iter); |
233 | std::size_t i = static_cast<std::size_t>(index); |
234 | buffers_[i] = this->make_buffer(b, &ctx, index); |
235 | |
236 | #if defined(BOOST_ASIO_HAS_IO_URING) |
237 | iovecs[i].iov_base = buffers_[i].data(); |
238 | iovecs[i].iov_len = buffers_[i].size(); |
239 | #endif // defined(BOOST_ASIO_HAS_IO_URING) |
240 | } |
241 | |
242 | #if defined(BOOST_ASIO_HAS_IO_URING) |
243 | if (n > 0) |
244 | { |
245 | service_->register_buffers(&iovecs[0], |
246 | static_cast<unsigned>(iovecs.size())); |
247 | } |
248 | #endif // defined(BOOST_ASIO_HAS_IO_URING) |
249 | } |
250 | |
251 | MutableBufferSequence buffer_sequence_; |
252 | std::vector<mutable_registered_buffer, |
253 | BOOST_ASIO_REBIND_ALLOC(allocator_type, |
254 | mutable_registered_buffer)> buffers_; |
255 | #if defined(BOOST_ASIO_HAS_IO_URING) |
256 | detail::io_uring_service* service_; |
257 | #endif // defined(BOOST_ASIO_HAS_IO_URING) |
258 | }; |
259 | |
260 | /// Register buffers with an execution context. |
261 | template <typename Executor, typename MutableBufferSequence> |
262 | BOOST_ASIO_NODISCARD inline |
263 | buffer_registration<MutableBufferSequence> |
264 | register_buffers(const Executor& ex, |
265 | const MutableBufferSequence& buffer_sequence, |
266 | constraint_t< |
267 | is_executor<Executor>::value || execution::is_executor<Executor>::value |
268 | > = 0) |
269 | { |
270 | return buffer_registration<MutableBufferSequence>(ex, buffer_sequence); |
271 | } |
272 | |
273 | /// Register buffers with an execution context. |
274 | template <typename Executor, typename MutableBufferSequence, typename Allocator> |
275 | BOOST_ASIO_NODISCARD inline |
276 | buffer_registration<MutableBufferSequence, Allocator> |
277 | register_buffers(const Executor& ex, |
278 | const MutableBufferSequence& buffer_sequence, const Allocator& alloc, |
279 | constraint_t< |
280 | is_executor<Executor>::value || execution::is_executor<Executor>::value |
281 | > = 0) |
282 | { |
283 | return buffer_registration<MutableBufferSequence, Allocator>( |
284 | ex, buffer_sequence, alloc); |
285 | } |
286 | |
287 | /// Register buffers with an execution context. |
288 | template <typename ExecutionContext, typename MutableBufferSequence> |
289 | BOOST_ASIO_NODISCARD inline |
290 | buffer_registration<MutableBufferSequence> |
291 | register_buffers(ExecutionContext& ctx, |
292 | const MutableBufferSequence& buffer_sequence, |
293 | constraint_t< |
294 | is_convertible<ExecutionContext&, execution_context&>::value |
295 | > = 0) |
296 | { |
297 | return buffer_registration<MutableBufferSequence>(ctx, buffer_sequence); |
298 | } |
299 | |
300 | /// Register buffers with an execution context. |
301 | template <typename ExecutionContext, |
302 | typename MutableBufferSequence, typename Allocator> |
303 | BOOST_ASIO_NODISCARD inline |
304 | buffer_registration<MutableBufferSequence, Allocator> |
305 | register_buffers(ExecutionContext& ctx, |
306 | const MutableBufferSequence& buffer_sequence, const Allocator& alloc, |
307 | constraint_t< |
308 | is_convertible<ExecutionContext&, execution_context&>::value |
309 | > = 0) |
310 | { |
311 | return buffer_registration<MutableBufferSequence, Allocator>( |
312 | ctx, buffer_sequence, alloc); |
313 | } |
314 | |
315 | } // namespace asio |
316 | } // namespace boost |
317 | |
318 | #include <boost/asio/detail/pop_options.hpp> |
319 | |
320 | #endif // BOOST_ASIO_BUFFER_REGISTRATION_HPP |
321 | |